diff --git a/custom_components/shopping_list_manager/models.py b/custom_components/shopping_list_manager/models.py
index 13736ac..b4d0680 100644
--- a/custom_components/shopping_list_manager/models.py
+++ b/custom_components/shopping_list_manager/models.py
@@ -132,7 +132,8 @@ class ShoppingList:
     # Ownership: None = visible to all users; set = private to owner + allowed_users
     owner_id: Optional[str] = None
     allowed_users: List[str] = field(default_factory=list)
-    
+    ha_todo_entity_id: Optional[str] = None
+
     def to_dict(self) -> Dict[str, Any]:
         """Convert to dictionary."""
         return asdict(self)
diff --git a/custom_components/shopping_list_manager/websocket/handlers.py b/custom_components/shopping_list_manager/websocket/handlers.py
index a93eb00..5423a51 100644
--- a/custom_components/shopping_list_manager/websocket/handlers.py
+++ b/custom_components/shopping_list_manager/websocket/handlers.py
@@ -341,6 +341,7 @@ async def websocket_create_list(
         vol.Optional("name"): str,
         vol.Optional("icon"): str,
         vol.Optional("category_order"): [str],
+        vol.Optional("ha_todo_entity_id"): vol.Any(str, None),
     }
 )
 @websocket_api.async_response
@@ -364,7 +365,9 @@ async def websocket_update_list(
         update_data["icon"] = msg["icon"]
     if "category_order" in msg:
         update_data["category_order"] = msg["category_order"]
-    
+    if "ha_todo_entity_id" in msg:
+        update_data["ha_todo_entity_id"] = msg["ha_todo_entity_id"]
+
     updated_list = await storage.update_list(list_id, **update_data)
     
     if updated_list is None: